How sound are the two hadiths: "Whoever fears something, it is made to dominate him," and "He who undertakes three things after Asr will regret it: washing, sleeping, and cupping"?

"That which one fears is made to have power over him" — we do not know of this having been mentioned in an authentic or weak hadith.

"He who undertakes three things after Asr regrets it: washing, sleeping, and cupping" — we do not know of any basis for this.

We have already discussed sleeping after Asr in fatwas numbered 41557 and 62513.

As for cupping: all hadiths regarding its timing are weak. Ibn Hajar said: "Since none of these hadiths are authentic, Hanbal ibn Ishaq said: 'Ahmad would perform cupping whenever his blood pressure rose, at any hour.'"

Indeed, there is a narration that indicates cupping after Asr, but it is not authentic. In Al-Majma', it is reported from Anas that he said: "Abu Tayba passed by us — I believe he said: after Asr in Ramadan — and said: 'I performed cupping for the Messenger of Allah, peace be upon him.'" This was narrated by Al-Bazzar, and its chain of narration includes Al-Rabi' ibn Badr, who is abandoned (in narrations).